SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2867145d93af3181c2229671199891e2af91be14ecc21ed275319802c2bc5c8c' 
  AND token = 'FlqrnauUh+ccEyZqgyxsGaOQygriMTOTCL/2H6jgv6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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