SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5402895c37ca17262b7d690ca7fcfca6d30986391b5f5a505c81a6185013eb1f' 
  AND token = 'Vs++IhwyijL8KleG2osYc0I6ZvXIM1JeIRlISehRXj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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