SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ae96d6c545cb227481137dd5ee978f1ae9c7844484bdca3d028b740d36042ff' 
  AND token = '6ovZRXkEifFIW1RNhpEeZkVG7zmUrrbEz/qyIE2k4W4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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