SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9e0f4f90dea908774325cab51d3eaea2cc192390f3488fe9d8ce09264c3cbaac' 
  AND token = 'UYuQgw4/Yl7Iw55ZtSyzoRYVrEH24LXoS3KFcHJk7Fo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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