SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b83d8b0f5d92c2684f9ec07608e92529632ea30147e1f7e6b8b68ca51f7206e5' 
  AND token = '9cq7FvIJzkj4Ss2RZRY8K/ByTweZ+sXp3Hbl0mkJS6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}