SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6b3b61f778b2804d70bef939f717e1d54a1f3823a9066cbf72891fc482044ae' 
  AND token = 'UwnzVKboSlzB8kntH1tdRaUO4w5Cx5y19qeebHa0Cfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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