SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a3dea6bfe2e923c1b5a266baa38d2b552d3f57742156a1da0b2a590ec62c8770' 
  AND token = 'x/Gvb296JC97PItGj41czPHjBdkcXJ+mF/tJ4xHBXzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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