SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db9bd51495ef856a7e7f1e7a139402f41160d8f0279a6966ffb55cc371cfeb83' 
  AND token = 'F1sXpkog0Ze39F6x5rqwebhOxOZJDNhSATiVjcUb4A4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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