SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebec1532c9de5b298a815711c7e0866ba494ff8f3945e0be94973a13273bf181' 
  AND token = 'LeWBvYg0lDfU7Eq5JpVGI4wFt1SUcwwP8JcMJgY12KI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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