SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6165f8ce1b27a1a344bb3969646721567b293025cb4308b4630d5d213102d3a' 
  AND token = 'kOCHsqhrgCMtWLEEjz8+ToZamyLPyDNii+hSHj8+vIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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