SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efccbe61034308508d9cd30a0b8ccc8031f6dcbdcf06490da8bab9219ae6b897' 
  AND token = 'YID5hjg5K6AuqNTYenyB9NBnTDqNU0rnx0LdgJVSUFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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