SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c15564225e5cf2438e36f153b7225d3e9e969da8919c3c774aeea707c557a727' 
  AND token = 'J+REkLhHzszTQ/fwsikiVeqeG2YKhJrmPxWfjTK4Mio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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