SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fbdc242992de25ad5223c2db338a4a8392ce58f5d8849f511d34333bc854e5b' 
  AND token = 'CEGoUYx9nw16qMbqOpxVI5mgS+syH1Ke0/YIYjbGtOs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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