SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9816aaf4f73c5d419410b985dbf520acfc36f720895a3819aa4bdb9b6cb2e07' 
  AND token = 'iZzYLSRYACvLoCvXSxo8pyU9NU4bQ1e3INeEoov/g28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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