SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4864bab7244514043899ed96ef09fcced2762149530fb13756e2b841dc3b0f5a' 
  AND token = 's7mOwZeIt2Wngnt3dkD+z3M6UK+Y9p4JhINXSwu/qHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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