SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '97e9a2bdb605789e19256132f71040569f574d92d42372636b33d75b2ed32b1f' 
  AND token = 'kgXK0PEfRCzcyw/BuwNlh9APfiSIFpvDDScSfljHK+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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