SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e111a1e1d78cd1e6d94799e9021c8871a2ad60990019a7be4dddbab1f1354950' 
  AND token = 'di/nX7ceYUXukPaW+dLqla0qsfw2jQ27G566xtDP2h4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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