SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e90357f8953fab359d3b3bd2b66a68c7e38472f8ff5dbff8ebc7b5ea7d0c72bc' 
  AND token = 'YktGins+zCeihQgCvF2gJmgVUrgFXqeUcJLQEOL6L0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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