SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b2baea2c544e39a6315cdd604ed7bc80d625652f2e6a48bcbf94bba038bd8a71' 
  AND token = 'a/CHLQYPWJeHOza/sl7I3w3tWxcftNT0fYX9oLYD2FA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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