SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '849c33bbc00887fd9f21c655d1ece94c2f19e05e579e7756f76962bc8d22c52a' 
  AND token = 'rLFFpwgUhP2Mm6xKm1JyQiaAYSjvVvFyxmJ9yOz6XCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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