SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a7f251126d6be715bdb98a15211752557ef1bee811ac92030832cee861e6422' 
  AND token = 'IsljbD+CdgBH6SEDneJ9e5LVbdD1PJCoYLxpOReD7mA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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