SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b4a0189826296017afbebb92bf96e3391a0912af25fe8a24bfe9c02e8ce9420' 
  AND token = 'lhMU8CzOBJP+gCqCkqekpnUKA7byWNkdcrGxEtZrLN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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