SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c66607140d7e5a247abc644cd55f7b12690291f775c46edc88d75e7071061fa6' 
  AND token = '9eNbqFS3g3PhxRs6+tOjxWPkh8WJbXyI/fTvUmTBEz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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