SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '43fb5022d53f44e6964dff7311751ab144deca7838a89baf2a29b5269b21a098' 
  AND token = 'gj9niTmpSvm87Su/XrsOJBPaeAcMxqo6SWaw+gnp6S8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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