SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '841d0c4158ebb6435cd5b574743866460472a747130dfcfba6028a738227b193' 
  AND token = 'jyQhG/MJCn1gLyxR3wG64frJVF9SxynNsmH1DIUx310=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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