SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '897ca5c202005e161f731e60a7835c865f73a4b5142eb6e8c68974549e0c2cfd' 
  AND token = 'g04PEWkwbiRJlr/nZb3L0oVxcZRMI7hp+EIojDRmxC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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