SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6b1488e31ef83c150435896ddc39cc5ca2922cd7cabafe676e1fde4e363e4523' 
  AND token = '7EjD8keAE/tduqTWyB27vXA21Jq89ECNPHxhrP+ywI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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