SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9e64483067e9d6626df8d7c12fd68031868609c36e40dd546ca09be592573912' 
  AND token = '83vIaoS1vSWSbz6krVre4Y+vDGtaByI0e9tKEI38l1o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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