SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5176004b9d98c665470c5102aec465ae776a051497a1a7ce1ec7c996cb8a2152' 
  AND token = 'ZieuaIrzP+B94RePsVvWIUPqg0vJ1eTrnNL0/VoBVDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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