SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a49dcedb98137a1c685c18ba56eefb161ed141d58bbf4d887667912848a58c34' 
  AND token = 'UO/NZnfOWGoER4zwpym/HJ10vgWByABJNnAFj0GK32I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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