SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f18c5665c16c8b860ce19233aa5d353ddd5fd8dfbbc5d123d7782a274094a052' 
  AND token = 't56XDxGY5Zb9UOwHMrVpAmjR2FMqJzGefLL2e/oPk9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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