SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d23ffe121bf975088ee3d752bd1658346a907cc686fb9072d17a78fe879e0f5' 
  AND token = 'T8m4zVBhYlvPp+cZ8lCr+Sn/bnV0f1JmgUFcivQrkf0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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