SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2c7f13bf2221daf9781967fccaeb415beff38e13da1684aa7514759d4a408013' 
  AND token = 'li/09ncSvslVBiMCq/KodFXRYcIooZw1/M77FcXUghs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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