SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2a58e09553d2947dd6e609228513ce2cb381401f662cafe4a3100bcdfa9de53' 
  AND token = 'OZJO0Rn306wzIZemmtxiX4HCH9UXdnzR1yGJNiPFtKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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