SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d8f7389616666802b5d4123fe6cb89ccb3095ef902fd1f902d2683deabad186' 
  AND token = 'NOz6XYQElYd3gdX8XpFt5DJWGQvJB5IPXbgZTm+bdNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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