SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '639fee515780116add79602736b5db20762d675d7d3e5745bc658e8670ec7678' 
  AND token = '/upMm5ri7lJydG5raqAVPm4OWuJtkg0KNjbAPhVxM98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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