SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7b90d8842ce67533fbd9358a1c6a15873e9a50ad733260f557b080a228ab5eca' 
  AND token = '/GAiYSLh17ksBrUECafxmQ5iRUa04xmpmDjDgTkrAr0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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