SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c567a95beef9c255d4771c7a7dfbbb0883f9fd6c9dddff53e410dec140980150' 
  AND token = '/unWgFssUimCocTznfr2KoOP5VYRlcbz3CRoSXT3Jnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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