SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcff04d51e0f5280552ec8d15ebc09893a68a8b852fc1a2ca9d5f37cbf231cd4' 
  AND token = 'pIiKD3DHMuBwvQIFw8hjJUkYHJWOxvTAChNU5qPpM04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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