SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0046555b2f5d442ced5da11506c5c62b87b3db2cd091b22ee63e1febf822b9cc' 
  AND token = 'lelfYKQgfz5JPafZ9sDuxCHpi20alCY1kDm2gZMN3CE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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