SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb79580ea2ae73fa142e6450b6b6079bddfa793fe617a8361f38ace77928e12c' 
  AND token = '1DOF8rWmsKlp6VZZaPbJ6UlduK1rwqSuh8l9UEDOYqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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