SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8b54c49b4282e6e576cc78171884b1d31dffdb74b0f3e79413cd1adea6f5276' 
  AND token = 'ftKZzjrLo0OCKOA6uNbydMj7GDhcmY9mqJDdXDqMb6A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}