SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e61d9f443ea85ffef2c9abebe16ff1ff11cb8cab637fd9d64acfd3108498db21' 
  AND token = 'v1jOp0wb186vgjFV7PRBnxHIji3faynNAvCoo8sb2hA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}