SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd2ae5afa7ce4a9e35bfac7258a8132a091f776817e40b6bd421e09549e0691a' 
  AND token = 'ex+b7mHISubNkJbbVrDC77uSpKrDVXqgSxCV365xUtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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