SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d2c8cf34d291ceb6cb1810b422295194d4c2913c674ac65fb754fb448ffc352' 
  AND token = 'uuJ9tB4DBa938xK97qcXwblz+oP6tKEXPLHlFCjq8T8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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