SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89e40e3f3f9a052542ba24b32235b7378ef87793f82658a6cc016c03de926cb2' 
  AND token = 'rsXIQlh2ppwZzm1ikuxlr2cRpo5aSMI7VbJJvFADYHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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