SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1852d09cf953d1cb77c9c7cc4db082537066ad8584aec82528c1cb6e9472faeb' 
  AND token = 'OEWiq+znN2ZaT8Uq+SJzAIhsVh7OJPZ/nT4Mj28q4w0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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