SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a53d3a4d12c5108dfb747bbe40d84c8d6b61c6e5fa3ce4f0d20c624910f081f' 
  AND token = 'CdjLeQ3H32nsFdKhXl1FYCPZv+gWYSUVemJgYK/6dFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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