SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2a9c83765d88d8324b4b04d84df8e64c648c50739e1d6abcc2c44bfde948c976' 
  AND token = '6yXxxPMWBshYXgIj8RO3nV2zx/JXOo8ZLCU1zO5/Czw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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