SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cd1673ef98d374e01c04a054c4053dcc83e5fe8c5f929c62b65b1336f635294' 
  AND token = 'sBnLFApYfCQxytIkvDFK4JTChqs+wB7ZJC+hs+GbCOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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