SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a4479f76405b0c00363dcee436f4bda7082f78674686b986513e784dd2acc5c' 
  AND token = 'BCiD9YbDRAn4c3528toFYyqgG/Ianv5uUpsQGgSf/aE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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