SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70990ebc911fe6a208cdd28ab783bc73aa00f4365ceaff5df42cea595b995890' 
  AND token = 'NiTtAFlJodLRxbRatnJc9pHRMfm6qM6g9fsqEKVcdsk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}