SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd8eb58c4c8b78b40d6cc901809113304d7c262ab790164f952ad0b4af5f203c' 
  AND token = 'OiNpDCo1BZWZYqbbiikSFm0ueMkfTztwiOTmRySct/0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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