SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '0b72ca1e1c1c06beeb734ede64e8f4719ad2d93bf52d896db300933b3ebdd996' 
  AND token = '/C3i7Rwr9ZmkU8dL+ommc7ZS+gQ3pRD5PuwvH/NhdNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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