SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a735840057fe443fe2a679f6de30697cfc97edd1f8d64628837dd8b4af85eadd' 
  AND token = 'SGyb6QsWA1RhFeCpNblsLGyshYxfZpbJuuLF/FHWcu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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