SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd6e8af3818607c19b04388ebeed5a7467ba6cc504d958bc79605df19634711b' 
  AND token = 'Hgw/Snuyaq2w9o+UkJUv5ubZpMJrBIWZobiBZMVFOvk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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