SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b888d699a5c15e2975df429b0cc882dcd89859909200ad7efe9cdbb2eb558b4' 
  AND token = 'O0GCsJaMcNblffvC0Pxo5ewgqDWVIbElDL76aTYdOIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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