SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79b832c78521098d8f90f14a3e235a7f8408ed2271c05944c5ce8a633a5a52e5' 
  AND token = '3RVNJbJXVE988zd9N3Xb82D/FuOGRloTR6974bBTDSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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