SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3e887fbcd63780ba8290cde2d53b5329c3b85e57120cdf019bbb23dec7d6ca42' 
  AND token = '264AFEPh+DbJvKKocy6IwrVX2j5UCLQP3YDKozLmStk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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