SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83378cf918f6581b9dda458f7f64f5ed54bc4b27f71e927bfa183fd58aa871f7' 
  AND token = 'a7QX0NiigpHSh9lxTsLEQnHY5EEPbDfigcMUrCpz2Ok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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