SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed348cbbac3a103dc3693e258291b31c2fde39f491b984f1fd49f1d1fa02b184' 
  AND token = 'bIalrK6Hq/LdQ8ENc3yjiRGskR/as/wQ+AnaAURN8Sc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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