SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1878486e9a5bd13f6812b69279935ece86cf3c85558f1c3c39d0d4650750f8b6' 
  AND token = '9xOU/aI8B88MyIeldFuhQh1jWIxkRqHJvz1zfpSXX/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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