SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '953868ecc99e69996d95b7b2518555e3e36235faee0a45f97206bc03c516ff87' 
  AND token = 'i/nV28eKf+gSSewPx0R3k2XviM0AtjewRuzWzugVFiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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