SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b223d4330154cd9cf1fdd3667f043026cd665acb95fcb39d357ac4fbf6ed8613' 
  AND token = 'sk1WYV5svI6DJrbmMq2KdrzB255opjyIIGRXCtUhLCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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