SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10b0049b459f6e0f2acd26108c331c884a70736399c6691f7178ca8934ab2c1d' 
  AND token = 'ne+z+GFNhYuXrSMElXO6Sp8Flj+iZnjoWn44gMeUXy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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