SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4bcc6e593134297793a5b9c67641a52e7464ed19e4ea1d550a957d032a62e0ba' 
  AND token = 'JOEQNx5LlulC1Rb5ZyguK7yM9IRu+iTp/RD1jMNhrdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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